Writing instrument



FIG. 1 is a front right perspective view of a writing instrument according to the present invention;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a back elevational view thereof;

FIG. 4 is a right side elevational view thereof;

FIG. 5 is a left side elevational view thereof;

FIG. 6 is an enlarged top plan view thereof; and,

FIG. 7 is an enlarged bottom plan view thereof. 

The ornamental design for a writing instrument, as shown and described. 